1. Technical Field
The present invention relates to communication in which multiple types of communication modes are used.
2. Related Art
Multiple types of communication modes are known, including telephone, videophone, fax, e-mail, and conference calling. Selecting the optimal communication mode from among these multiple types of communication modes can be a troublesome process for a user.
Accordingly, in, for example, JP-A-2007-166322, a server executes presence management when a session has been established between client terminals, managing which communication method can be used by each client terminal; presence information expressing what communication methods can be used by one of the client terminals is provided to the other client terminal.
Furthermore, in, for example, International Publication NO 2005/053298 pamphlet, in order to switch from a telephone function to a fax function, the telephone device of one user acquires the fax number of the fax terminal of another user from the telephone device of that other user, transmits the acquired fax number to the fax terminal of the one user, and the fax terminal of the one user then transmits a fax to the received fax number.
A case is conceivable where, for example, one user attempts to switch the communication mode s/he is using with another user from conversation over mobile telephones (telephony) to videoconferencing using personal computers.
In such a case, using the technique described in JP-A-2007-166322, the one user can discover the communication methods that the mobile telephone of the other user can use by viewing the presence information provided by the server, and then execute one of those communication methods. However, with this technique, it is necessary for the one user to identify the communication method that should be executed by the mobile telephone of the other user by him/herself, and furthermore, the one user cannot discover information regarding communication terminals aside from the mobile telephone of the other user.
Meanwhile, in the same case, using the technique described in International Publication NO 2005/053298 pamphlet, the one user can discover communication address information regarding communication terminals aside from the mobile telephone of the other user. However, the one user can only discover communication address information regarding communication terminals aside from the mobile telephone of the other user from the mobile telephone that the other user is currently using. In order to discover the communication address information after the conversation using the mobile telephone has ended, it is necessary to once again initiate a conversation using the mobile telephone.